جستجوی مقالات مرتبط با کلیدواژه "uniquac" در نشریات گروه "مهندسی شیمی، نفت و پلیمر"

Recovery of propionic acid from aqueous solution is economically and environmentally important. In this study, the liquid-liquid equilibrium data of water + propionic acid + cyclic alcohols (cyclopentanol and cyclohexanol) ternary system was obtained at 303.2, 313.2, and 323.2 K temperatures. These ternary systems exhibit type-1 behavior of liquid-liquid equilibrium (LLE). The Hand and Bachman equations confirm the validity of the measured data. For correlation of liquid-liquid equilibrium data, the NRTL and UNIQUAC thermodynamic models have been used and the inter-molecular interactions coefficients have been determined. RMSD values for NRTL and UNIQUAC models in cyclopentanol containing systems were 0.0107 and 0.0057, respectively, for cyclohexanol 0.0108 and 0.0076 respectively, which showed the accuracy of these models in correlation liquid-liquid equilibrium data. The values of the selectivity factor for both solvents larger than the unit are obtained, which shows that these solvents can be used to extract propionic acid from aqueous solution.

Biodiesel is a substitute for fossil fuels which is produced through a transesterification reaction between vegetable oils or animal fats and light alcohols such as methanol or ethanol. In this reaction, along with the production of biodiesel, glycerol as a byproduct and non-reacted alcohol that reduces biodiesel quality is produced. Hence, many studies have been carried out on liquid-liquid equilibrium (LLE) for ternary systems containing biodiesel + glycerol + alcohol. Two phases are formed as 1-rich in biodiesel and 2-rich in glycerol; moreover, alcohol is distributed between these two phases. In this work, based on previous experimental data, the UNIQUAC and NRTL thermodynamic models were used to forecast the composition of the phases. The intermolecular interaction term for each of the models was considered as a linear function of the reverse temperature. In both models, there was no difference between the amount of biodiesel produced from different oils and obtained from the general interaction parameters. Based on the results, the percentage of absolute average deviation for NRTL and UNIQUAC models for biodiesel + glycerol + ethanol system were 1.24% and 2.13%, respectively, and for biodiesel + glycerol + methanol system was 1.13% and 1.71%, respectively.

In this study, NRTL and UNIQUAC thermodynamic models were used to predict the composition of ternary mixtures of solvents m/o/p-cresol water in organic and aqueous phases. Various solvents are used for the separation of cresols from water. In this study, methyl propyl ketone, methyl isopropyl ketone, methyl butyl ketone, and methyl isobutyl ketone solvents were investigated. Intermolecular interaction parameters were considered to be a function of temperature. The binary interaction parameters of water and cresols (m, o, or p) in the presence of each type of solvent were considered to be the same. Also, regardless of the type of cresol (m, o, or p), the parameters of binary interaction between water and each solvents were considered to be the same. The results proved the accuracy of the presented models, though the parameters of binary interaction parameters were considered to be the same. The root mean square deviation for NRTL and UNIQUAC models was 0.0086 and 0.0089, respectively.